Implantable medical devices (IMDs) are commonly used to provide treatment to patients. Implantable medical devices can include cardiac rhythm management devices and neurological stimulation devices, amongst others.
Some types of implantable medical devices deliver electrical stimuli to a target tissue via a lead wire (“stimulation lead”) or catheter having one or more electrodes disposed in or about the target tissue. In the context of cardiac rhythm management devices, the electrical stimuli can be delivered in the form of pacing pulses to pace the heart and/or relatively high energy defibrillation shocks or cardioversion shocks to terminate arrhythmias.
However, in some instances, a device may deliver a shock to a patient even when that patient is not experiencing a potentially dangerous arrhythmia. See, e.g., Spragg, Heart Rhythm, 5(5):762-765 (May 2008). This can be due to the device erroneously sensing the presence of an arrhythmia, which can in turn be the result of the inherent difficulties of accurately sensing cardiac activity and also a desire to value patient safety over patient comfort. However, unnecessary shocks can cause patient distress and can deplete battery life, amongst other things.
Endothelin-1 (ET-1) is a vasoconstricting peptide produced primarily in the endothelium. In addition to its role in vasoconstriction, ET-1 also plays a role in exerting bronchoconstriction and vascular and airway cell proliferation, via ETA and ETB receptors.